The present invention relates generally to a method for making electrodes for a battery, and, more particularly, to a solution-route method for making a thin film anode and a thin film cathode for use in a thin film battery.
The development of small, light-weight, power sources is being driven by the need for smaller electronic devices and emerging technologies, such as the autonomous micro- and meso-machines (MEMS) which are be developed for use as early warning detection agents in the fight against terrorism and counter proliferation. Power sources that possess the requisite power and energy to operate these small devices, such as micro-machines, sensors, transmitters, and other electronic circuitry without substantially increasing the final size of the device are necessary to achieve autonomy as well as to aid in the covert nature of some of these devices. Currently, these MEMS devices are being operated by very large power sources, in comparison to the final device size. An integrated power source that will not substantially increase the weight or size of the device that can be conformally added to a device is of high interest. Thin film batteries are an attractive alternative power source for these applications; however, existing thin film batteries are inadequate to meet these needs. Required for development of thin film batteries are materials that can be deposited as thin films for use as electrodes, both anodes and cathodes, where an electrode is a material that can transmit a current and, for practical use, can be cycled as demonstrated by voltammagrams.
Thin film batteries fabricated using a fast, inexpensive solution process approach can be conformally coated onto a variety of surfaces as a thin layer device (thinner than a sheet of paper) and can be designed as an integral part of a system, adding flexibility to the design of technologies, as well as reducing weight of the device without sacrificing mission capabilities. A thin film battery configuration also lends itself to a wide variety of series/parallel interconnect schemes, allowing for wide variability in the performance (for example, power, and run time) of the system.
The solution-based method of the present invention provides means for forming thin film anodes and cathodes required for developed of a thin film battery.